Fisiología respiratoria: el control de la respiración / Respiratory fisiology: the breath control

El control de la respiración comprende un componente automático involuntario y un componente voluntario, con centros de control en el tronco encefálico, principalmente en la médula oblonga y en el puente, y en la corteza cerebral. Estos centros reciben aferencias provenientes de sensores que detectan señales químicas y no químicas, interactúan entre sí y generan respuestas que llegan a las neuronas motoras inferiores a nivel de médula espinal. Estos procesos determinan el funcionamiento de los músculos implicados en la respiración, y de ese modo permite garantizar que los niveles de pO2 p CO2 y pH en la sangre arterial se mantengan en forma óptima, frente a diferentes situaciones y demandas metabólicas. Se hace una revisión actualizada del tema que permita comprender estos procesos.

The control of breathing comprises an involuntary automatic component and a voluntary component, with control centers in the brain stem, mainly in the medulla oblongata and in the bridge, and in the cerebral cortex. These centers receive afferences from sensors that detect chemical and non-chemical signals, interact with each other and generate responses that reach the lower motor neurons at the spinal cord level. These processes determine the functioning of the muscles involved in breathing, and thus ensure that the levels of pO2 p CO2 and pH in arterial blood are optimally maintained, in the face of different situations and metabolic demands. An up-to-date review of the subject is carried out to understand these processes.

Cortical Brain Functions ­ The Brodmann Legacy in the 21st Century

In 1909, Korbinian Brodmann described 52 functional brain areas, 43 of them found in the human brain. More than a century later, his devoted functional map was incremented by Glasser et al in 2016, using functional nuclear magnetic resonance imaging techniques to propose the existence of 180 functional areas in each hemisphere, based on their cortical thickness, degree of myelination (cortical myelin content), neuronal interconnection, topographic organization, multitask answers, and assessment in their resting state. This opens a huge possibility, through functional neuroanatomy, to understand a little more about normal brain function and its functional impairment in the presence of a disease.

Benign ovarian lesions with restricted diffusion / Lesões ovarianas benignas com restrição na difusão

Abstract Developments in magnetic resonance imaging have expanded its role in the assessment of the female pelvis, including the diagnosis of ovarian lesions. In this setting, diffusion-weighted imaging has proven its diagnostic value, which is particularly important in differentiating between benign and malignant ovarian tumors. In general, the latter show restricted diffusion, whereas the former do not. Exceptions include teratomas, endometriomas, hemorrhagic cysts, ovarian abscesses, ovarian infarction, and some benign stromal tumors. The aim of this review is to draw attention to benign ovarian lesions with restricted diffusion, with a special focus on diffusion-weighted imaging pearls and pitfalls.

Resumo Os recentes desenvolvimentos nas técnicas de ressonância magnética aumentaram o seu papel na avaliação da pelve em mulheres, incluindo o diagnóstico de lesões ovarianas. A imagem ponderada em difusão comprovou ter um valor diagnóstico indiscutível, fato particularmente importante na diferenciação entre tumores ovarianos benignos e malignos. Em geral, os últimos têm restrição na difusão, enquanto os primeiros não. As exceções incluem teratomas, endometriomas, cistos hemorrágicos, abcessos ovarianos, enfarte ovariano e alguns tumores benignos do estroma ovariano. Esta revisão tem como objetivo expor lesões ovarianas benignas com restrição na difusão, com especial enfoque nas pérolas e armadilhas da imagem ponderada em difusão.

Controle neural da deglutição / Neural control of swallowing

ABSTRACT BACKGROUND: Swallowing is a motor process with several discordances and a very difficult neurophysiological study. Maybe that is the reason for the scarcity of papers about it. OBJECTIVE: It is to describe the chewing neural control and oral bolus qualification. A review the cranial nerves involved with swallowing and their relationship with the brainstem, cerebellum, base nuclei and cortex was made. METHODS: From the reviewed literature including personal researches and new observations, a consistent and necessary revision of concepts was made, not rarely conflicting. RESULTS AND CONCLUSION: Five different possibilities of the swallowing oral phase are described: nutritional voluntary, primary cortical, semiautomatic, subsequent gulps, and spontaneous. In relation to the neural control of the swallowing pharyngeal phase, the stimulus that triggers the pharyngeal phase is not the pharyngeal contact produced by the bolus passage, but the pharyngeal pressure distension, with or without contents. In nutritional swallowing, food and pressure are transferred, but in the primary cortical oral phase, only pressure is transferred, and the pharyngeal response is similar. The pharyngeal phase incorporates, as its functional part, the oral phase dynamics already in course. The pharyngeal phase starts by action of the pharyngeal plexus, composed of the glossopharyngeal (IX), vagus (X) and accessory (XI) nerves, with involvement of the trigeminal (V), facial (VII), glossopharyngeal (IX) and the hypoglossal (XII) nerves. The cervical plexus (C1, C2) and the hypoglossal nerve on each side form the ansa cervicalis, from where a pathway of cervical origin goes to the geniohyoid muscle, which acts in the elevation of the hyoid-laryngeal complex. We also appraise the neural control of the swallowing esophageal phase. Besides other hypotheses, we consider that it is possible that the longitudinal and circular muscular layers of the esophagus display, respectively, long-pitch and short-pitch spiral fibers. This morphology, associated with the concept of energy preservation, allows us to admit that the contraction of the longitudinal layer, by having a long-pitch spiral arrangement, would be able to widen the esophagus, diminishing the resistance to the flow, probably also by opening of the gastroesophageal transition. In this way, the circular layer, with its short-pitch spiral fibers, would propel the food downwards by sequential contraction.

RESUMO CONTEXTO: A deglutição é um processo motor com muitas discordâncias e de difícil estudo quanto a sua neurofisiologia. Talvez por essa razão sejam tão raros os artigos sobre esse tema. OBJETIVO - Descrever o controle neural da mastigação e a qualificação do bolo que se obtém durante a fase oral. Revisar os nervos cranianos envolvidos com a deglutição e suas relações com o tronco cerebral, cerebelo, núcleos de base e córtex. MÉTODOS: Revisão da literatura com inclusão de trabalhos pessoais e novas observações buscando dar consistência a necessária revisão dos conceitos, muitas vezes conflitantes. RESULTADOS E CONCLUSÃO: Em relação a fase oral da deglutição consideramos o controle neural em cinco distintas possibilidades. Fase oral nutricional voluntária, fase oral cortical voluntária primaria, fase oral semiautomática, fase oral em goles subsequentes e fase oral espontânea. Em relação ao controle neural da fase faríngea da deglutição, pode-se observar que o estímulo que dispara a fase faríngea não é o toque produzido pela passagem do bolo, mas sim a distensão pressórica, tenha ou não conteúdo em passagem. Na deglutição nutricional, alimento e pressão são transferidos, mas na fase oral da deglutição primária cortical somente pressão é transferida e temos resposta faríngea similar a nutricional. A fase faríngea incorpora como parte de sua dinâmica as atividades orais já em curso. A fase faríngea se inicia por ação do plexo faríngeo composto pelos nervos glossofaríngeo (IX), vago (X), e acessório (XI), com envolvimento do trigêmeo (V), do facial (VII), glossofaríngeo (IX) e hipoglosso (XII). O plexo cervical (C1, C2), e o nervo hipoglosso, a cada lado, formam a alça cervical de onde, com origem cervical, um ramo segue para o músculo gênio-hioide, um músculo que atua na dinâmica de elevação do complexo hiolaríngeo. Foi também considerado o controle neural da fase esofágica da deglutição. Além de outras hipóteses foi considerado que é possível que a camadas musculares consideradas como longitudinal e circular para o esôfago sejam a longitudinal composta por fibras espirais de passo longo e a circular por fibras espirais de passo curto. Essa morfologia associada ao conceito de preservação de energia, nos permite admitir que a contração da camada longitudinal por seu arranjo espiral seja capaz de alargar o esôfago diminuindo sua resistência ao fluxo e provavelmente e também abrindo a transição esofagogástrica. Desse modo a camada circular, espiral de passo curto, pode propelir o bolo por constrição sequencial de cranial para caudal.

Valores de normalidade de um novo sistema de manometria de alta resolução por perfusão de água / Normative values for a new water-perfused high resolution manometry system

ABSTRACT BACKGROUND: Esophageal manometry is the most reliable method to evaluate esophageal motility. High resolution manometry (HRM) provides topographic contour colored plots (Clouse Plots) with simultaneous analysis from the pharynx to the stomach. Both solid state and water-perfused systems are available. OBJECTIVE: This study aims to determinate the normative data for a new water-perfused HRM. METHODS: HRM was made in 32 healthy volunteers after 8 hours fasting. HRM system used consisted of a 24-channel water-perfused catheter (Multiplex, Alacer Biomedica, São Paulo, Brazil). The reusable catheter is made of polyvinyl chloride (PVC) with 4.7 mm of diameter. Side holes connected to pressure transducers are spaced 2 cm for the analysis from the pharynx to the lower esophageal sphincter (LES). Holes are spaced 5 mm and 120° in a spiral disposition in the LES area. The sensors encompass 34 cm in total. Upper esophageal sphincter (UES) parameters studied were basal and relaxation pressures. Esophageal body parameters were distal contractile integral (DCI), distal latency (DL) and break. LES parameters studied were basal pressure, integrated residual pressure (IRP), total and abdominal length. Variables are expressed as mean ± standard deviation, median (interquartile range) and percentiles 5-95th. RESULTS: All volunteers (17 males, aged 22-62 years) completed the study and tolerated the HRM procedure well. Percentiles 5-95th range were calculated: Upper Esophageal Sphincter (UES) basal pressure 16.7-184.37 (mmHg), DL: 6.2-9.1 (s), DCI: 82.72-3836.61 (mmHg.s.cm), break: <7.19 (cm), LES basal pressure: 4.89-37.16 (mmHg), IRP: 0.55-15.45 (mmHg). CONCLUSION: The performance and normative values obtained for this low-cost water-perfused HRM seems to be adequate for clinical use.

RESUMO CONTEXTO: Manometria esofágica é o exame mais confiável para avaliar motilidade esofágica. Manometria esofágica de alta resolução (MAER) apresenta um gráfico dinâmico e colorido (Clouse plots) com análise simultânea da faringe ao estomago. Dois tipos de manometria estão disponíveis: estado sólido e por perfusão de água. OBJETIVO: Determinar os valores de normalidade de um novo sistema de manometria de alta resolução. MÉTODOS: MAER foi realizada em 32 voluntários saudáveis após jejum de oito horas. O sistema utilizado é de perfusão de água com 24 sensores (Multiplex, Alacer Biomedica, São Paulo, Brasil). O catéter permanente é feito de cloreto de polivinil (PVC) com 4,7 mm de diâmetro. Os orifícios laterais para conexão com os transdutores de pressão são espaçados de 2 cm para análise da faringe ao esfíncter esofagiano inferior (EEI) e são esparçados em 5mm em forma espiralada com 120° entre orificios. Os sensores no total englobam 34 cm. Para o esfíncter esofágico superior (EES), os parâmetros estudados foram às pressões basal e de relaxamento. Os parâmetros do corpo esofágico foram: integral de contratilidade distal (DCI), latência distal (DL) e quebra. Os parâmetros do EEI inferior foram pressões basal e de relaxamento e pressão de relaxamento integrada (IRP). As variáveis foram expressas em medias ± desvio padrão, medianas (variação de interquartis) e percentis 5-95. RESULTADOS: Todos os voluntários (17 homens, com idade variando entre 22-62 anos) terminaram e toleraram o exame. A variação dos percentis 5-95 foi calculada: pressão basal do esfíncter esofágico superior (EES) foi 16,7-184,37 (mmHg), DL: 6,2-9,1 (s), DCI: 82,72-3836,61 (mmHg.s.cm), quebra: <7,19 (cm), pressão basal do EEI: 4,89-37,16 (mmHg), IRP: 0,55-15,45 (mmHg). CONCLUSÃO: A realização dos testes e os valores de normalidade determinados por este estudo parecem ser adequadas para a prática clínica.

Anatomía, fisiología y rol clínico de la corteza vestibular / Anatomy, physiology and clinical role of the vestibular cortex

El sistema vestibular, mediante sus órganos periféricos, nos permite procesar correctamente los cambios de aceleración angular de la cabeza y lineal del cuerpo y así permitirnos una correcta orientación en el espacio. Esta información sensorial es dirigida hacia los núcleos vestibulares y desde aquí se comunica con los núcleos óculo-motores y estructuras del tálamo a través de tractos ascendentes del tronco encefálico. Posteriormente la información se dirige hacia centros subcorticales y corticales de naturaleza eminentemente multisensorial. La naturaleza y función de estas estructuras es controversial. En esta revisión se abordan los principales conceptos y descubrimientos a nivel de investigación básica y clínica del procesamiento cortical generado por estimulación de tipo vestibular.

The vestibular system, thanks to its peripheral organs, allows us to properly process the angular head movements and linear acceleration in order to give us a proper orientation in space. The information from these sensory inputs is routed to the vestibular nuclei and thence ascending tracts of the brainstem, which communicate with the oculomotor nuclei of the thalamus and structures. Then the information goes to subcortical and cortical centers, which are eminently multisensory nature. The nature and function of these structures are controversial. In this review the main concepts and discoveries at the level of basic and clinical research generated cortical processing of vestibular stimulation are addressed.

La Insulectomía podría ser un abordaje ideal para crisis insulares y peri-insulares? / Insulectomy for insular and peri-insular seizures could be an ideal and safe approach?

La insulectomía es una técnica microquirúrgica establecida para el tratamiento de la epilepsia refractaria al tratamiento farmacológico. El origen insular de la epilepsia es inusual, sin embargo, con la investigación a través de electrodos híbridos este tipo de epilepsia ha incrementado su diagnóstico. Los autores hacen hincapié en las funciones insulares, así como los puntos de referencia anatómicos para la cirugía. Se discuten las principales complicaciones y las bases fisiológicas para las indicaciones de cirugía.

Insulectomy is an established microsurgical technique for treatment of insular epilepsy refractory to clinical management. The insular origin of epilepsy is unusual, however with depth investigation through hybrids electrodes such kind of epilepsy is increasing its diagnosis. The authors emphasizes the insular functions as well as the anatomical landmarks for surgery. The main complications are discussed and physiological basis for indications.

Aportes sobre el correlato neuroanatómico de la personalidad / Contributions on neuroanatomical correlate of personality

Concept of personality is refers to stable and relevant attributes of a person, that explain consistent behavior patterns. Many researchers have different brain areas involved in controlling personality. Several highlighted the role of the orbitofrontal cortex in the ability to reverse the association between stimulus and reinforcement, others associated it later with the prediction ofsensory events subsequent results. The medial frontal cortex has been involved with functions as the control of actions, monitoring results as punishments and rewards, personal perception of stimuli and social cognition. Others include the lateral prefrontal cortex in complex issues of valuation. Finally, the anterior temporal region is considered to be related with facial recognition and social knowledge. In this paper we review evidence available in today’s literature about the neuroanatomical substrate ofpersonality, and its application to the study of two disorders: psychopathy and borderline personality disorder. Understanding this substrate could mean a contribution for treatment.

La personalidad corresponde a aquellos atributos estables y relevantes de una persona, que explican patrones consistentes de comportamiento. Muchos investigadores han implicado distintas áreas cerebrales en el control de la personalidad. Varios destacaron el papel de la corteza orbitofrontal en la capacidad de revertir la asociación estímulo refuerzo y posteriormente en la predicción de resultados posteriores a eventos sensoriales. Se ha involucrado a la corteza medial frontal en funciones como el control de las acciones, el monitoreo de resultados como castigos y recompensas, la percepción personal de estímulos y la cognición social. Otros incluyen a la corteza prefrontal lateral en aspectos complejos de la valoración. Por último, se considera a la región temporal anterior en el reconocimiento facial y también en el conocimiento social. En la presente revisión se expone parte de la evidencia disponible en la actualidad en la literatura, acerca del sustrato neuroanatómico de la personalidad y su aplicación al estudio de dos patologías: la psicopatía y el trastorno limítrofe. La comprensión de este sustrato puede significar un aporte para el tratamiento.

Estructuras cerebrales implicadas en el procesamiento temporal / Brain structures involved in temporal processing

El tiempo siempre ha sido una constante regulatoria del comportamiento humano. Durante las últimas dos décadas, la neurociencia ha buscado las bases biológicas al igual que la localización específica de estructuras o sistemas que el cerebro humano utilice en la ejecución, interpretación o retención de procesamientos temporales. La presente revisión reúne gran parte de los estudios actuales enfocados en la ubicación de las estructuras que involucran lapsos de retención, cronometraje o procesamiento temporal, reportando evidencia respecto a diversas estructuras involucradas, como lo son los ganglios basales; en la activación del putamen respecto a conteos dentro de respuestas motoras; Al cerebelo, en relación a intervalos de duración relativamente breves de tiempo, que van desde 300, 400, 600 y 800 ms, hasta 1-2 o 12-24 segundos; En la relación entre amígdala y corteza insular, en la ejecución de cronometraje controlado; En corteza frontal/pre-frontal, asociado a períodos breves (menores a 1 s) o al menor rendimiento de procesos atencionales o de memoria, propios del funcionamiento ejecutivo; y corteza parietal, asociada a la comparación consiente de las duraciones en rango de segundos (intervalos de 1 s) en relación a señales auditivas y visuales, así como en la codificación espacial y el procesamiento de cantidades numéricas. La localización de estas estructuras es la base para el desarrollo de modelos de estudio e integración de sistemas cada vez más precisos respecto a cómo el cerebro humano interpreta el tiempo...

Time has always been a constant regulatory human behavior. During the past two decades, neuroscience has sought the biological basis as the specific location of structures or systems that use the human brain in the execution, interpretation or retention of time processing. The present revision gathers much of the current research focused on the location of structures that involve retention periods, timing or temporal processing, reporting evidence regarding various structures involved, such as the basal ganglia, in the putamen regarding activation counts within motor responses; The cerebellum, in relation to a relatively short duration intervals of time, ranging from 300, 400, 600 and 800 ms, 1-2 or 12-24 seconds; In the relationship between amygdale and insular cortex, in performing timing control; In frontal/prefrontal cortex, associated with brief periods (less than 1-s) or lower yield of attention or memory processing, typical of executive functioning; And parietal cortex associated consents comparison of durations in seconds range (1-s intervals) in relation to auditory and visual cues, as well as spatial encoding and processing numerical quantities. The location of these structures is the basis for the development of study models and integration systems increasingly accurate as to how the human brain interprets the time...

Cognitive mechanisms and motor control during a saccadic eye movement task: evidence from quantitative electroencephalography / Mecanismos cognitivos e controle motor durante uma tarefa de movimento sacádico dos olhos: evidências de eletroencefalografia quantitativa

The saccadic movement is an important behavioral measure used to investigate several cognitive processes, including attention and sensorimotor integration. The present study aimed at investigating changes in beta coherence over frontal, motor, occipital, and parietal cortices during the performance of two different conditions of a prosacadic paradigm. The conditions involved a different pattern of stimulus presentation: a fixed and random stimulus presentation. Twelve healthy volunteers (three male, mean age of 26.25 (SD=4.13) performed the task, while their brain activity pattern was recorded using quantitative electroencephalography. The results showed an interaction between factors condition and moment for the pair of electrode C3/C4. We observed a main effect for moment to CZ/C4, FZ/F3, and P3/PZ. We also found a main effect for condition to FZ/F4, P3/P4, and O1/O2. Our results demonstrated an important role of the inter-connection of the two hemispheres in visual search and movement preparation. The study demonstrates an automation of action and reduction of the focus of attention during the task. We also found that the inter-hemispheric beta coherence plays an important role in the differentiation of the two conditions, and that beta in the right frontal cortex is able to differentiate the conditions, demonstrating a greater involvement of procedural memory in fixed condition. Our results suggest a neuronal specialization in the execution of prosacadic paradigm involving motor task sequence.

O movimento sacádico é uma importante medida de comportamento usada para investigar vários processos cognitivos, incluindo atenção e integração sensório-motora. O presente estudo teve como objetivo investigar as mudanças na coerência em beta nos córtices frontal, motor, parietal e occipital durante a realização de duas condições diferentes de um paradigma do movimento sacádico. As condições envolveram um padrão diferente de apresentação do estímulo: a apresentação do estímulo fixo e do aleatório. Doze voluntários saudáveis ​​(três do sexo masculino, com idade média de 26,25; DP=4,13) realizaram a tarefa, enquanto o seu padrão de atividade cerebral era monitorado, usando eletroencefalografia quantitativa. Os resultados mostraram uma interação entre condição dos fatores e momento para o par de eletrodos C3/C4. Observou-se um efeito principal ao momento para CZ/C4, FZ/F3 e P3/PZ. Encontrou-se também um efeito principal à condição para FZ/F4, P3/P4 e O1/O2. Os resultados demonstram um importante papel da ligação interconexão entre os dois hemisférios, em busca visual e preparação do movimento. O estudo demonstra uma automatização da ação e uma redução do foco de atenção durante a tarefa. Identificou-se também que a coerência em beta entre regiões inter-hemisféricas desempenha um papel importante na diferenciação entre as duas condições. Ainda, beta no córtex frontal direito é capaz de diferenciar as condições, demonstrando-se um maior envolvimento da memória de procedimento em condição fixa. Sendo assim, os presentes resultados sugerem especialização neuronal na execução do paradigma prossacádico envolvendo sequência de tarefa motora.

Interocepción y corteza insular: convergencia multimodal y surgimiento de la conciencia corporal / Interoception and insular cortex: multimodal convergence and the emergence of body awareness

La interocepción como censado del estado homeostático y visceral, ha sido recientemente postulada como requisito para la conciencia de estados emocionales corporales (Craig, 2009). Vías parasimpáticas y espinotalámicas que codifican esta información corporal tienen relevo en la corteza insular. Simultáneamente, han sido descriptas otras funciones insulares implicadas en procesos conscientes, como la intencionalidad, la toma de decisiones, la conciencia sensorio-motora, la percepción temporal, reconocer la imagen visual de uno mismo o percibir confiables a otros individuos (Craig, 2009; Ibanez, Gleichgerrcht, & Manes, 2010). Esta evidencia, sumada a resultados de estudios de lesión y neuroimágenes funcionales, sugiere que la corteza insular anterior (IA) sería la encargada de integrar señales multimodales cognitivas, emocionales y sociales para dirigir las conductas motivacionales que entrañan la supervivencia del individuo. En esta revisión analizamos el cúmulo de evidencia que involucran a la interocepción y al procesamiento insular integrativo en el surgimiento de estados emocionales conscientes, a través de estudios de lesiones y de técnicas de conectividad funcional en resonancia magnética funcional (RMF).

Recent research have suggested that interoception, defined as the sensing of homeostatic and visceral state, is a prerequisite for the emerging of conscious body feelings (Craig, 2009). Parasympathetic and spinothalamic pathways coding such information from the body have their final station in insular cortex neurons. At the same time, several other cognitive functions related to awareness, have been associated with insular activation such as intentionality, decision making, sensory motor consciousness, time perception, recognition of self´s image, or trust on someone else (Craig, 2009; Ibanez et al., 2010). Lesion studies and functional neuroimaging research is in line with this evidence, suggesting that anterior insular cortex would be engaged in integrate multimodal cognitive, emotional and social information in order to modulate motivational behavior leading to the survival of the individual. In this review, we analyze last research works on interoception and integrative insular processing through lesion studies and functional connectivity in functional magnetic resonance imaging (FC-fMRI).

Neuroanatomical aspects of the body awareness

The cerebral cortex is the most complex part of the human brain and is responsible for thinking, reasoning, cognitive functions, memory and sensory perception processes, among others. The cerebral cortex can be classified into areas, from the specific functions it performs. Particularly noteworthy are the cortical areas, which integrate from multimodal stimuli and enable the individual to perceive his own body and its relationship with the space around it. This capacity is built from the attitudes and values that the individual has in relation to his or her body (body image) and the dimensional perception of its segments (body schema). This process depends on complex neural mechanisms that are related to different cortical areas. The aim of this study was to compare the cortical areas involved in the construction of body perception: body image and schema. As a result, it was observed that the areas with predominance in the perception of body size are more related to the right parietal region and those related to cognitive aspects are located in the prefrontal area and parts of the limbic system.

Correlação entre espessura cortical frontal e desempenho de funções executivas em pacientes com infecção pelo vírus da imunodeficiência humana / Correlation between frontal cortical thickness and executive functions performance in patients with human immunodeficiency virus infection

OBJETIVO: Investigar a relação entre a espessura cortical medida pela ressonância magnética em regiões frontais e o desempenho em instrumentos que avaliam funções executivas em pacientes com HIV positivo. MATERIAIS E MÉTODOS: Participaram deste estudo 22 pacientes HIV-positivos, com déficits em funções executivas, sob terapia antirretroviral, idades entre 45 e 65 anos e escolaridade entre 3 e 20 anos. Foi realizada ressonância magnética com sequências convencionais, T1 3D, processado pelo Freesurfer para verificar espessura cortical. Instrumentos de avaliação das funções executivas: Teste de Trilhas, Wisconsin, Hayling, Dígitos (WAIS-III), fluência verbal ortográfica e Stroop. Para análise da relação espessura versus cognição, utilizou-se coeficiente de correlação de Pearson. RESULTADOS: Correlações significativas foram encontradas entre escores de: Wisconsin e espessura das regiões pré-central e orbitofrontal lateral à direita e pré-central esquerda; Teste de Trilhas e espessura da área pré-central direita e cíngulo anterior caudal esquerdo; e Teste Hayling e espessura da área lateral orbitofrontal esquerda. CONCLUSÃO: As correlações existentes entre medidas de espessura cortical pela ressonância magnética e desempenho cognitivo sugerem que os déficits executivos em pacientes HIV-positivos relacionam-se a uma redução da espessura cortical das regiões frontais.

OBJECTIVE: To investigate the correlation between frontal regions cortical thickness measured by magnetic resonance imaging of HIV-positive patients and their performance on instruments for assessing executive functions. MATERIALS AND METHODS: The present study included 22 HIV-positive patients in the age range from 45 to 65, schooling ranging between three and 20 years, with executive functions deficit and undergoing antiretroviral therapy. Magnetic resonance imaging was performed with conventional T1-weighted, 3D sequences and the images were processed with the Freesurfer software to measure cortical thickness. The following instruments were utilized to evaluate the patients' executive functions: Trail Making, Wisconsin, Hayling, working memory (WAIS-III), verbal fluency and Stroop tests. The Pearson's correlation coefficient was utilized in the data statistical analysis. RESULTS: Significant correlations were found between: Wisconsin scores and the thickness of the right pre-central, lateral and left pre-central orbitofrontal regions; Trail Making scores and thickness of right pre-central and left anterior caudal cingulate areas; and Hayling Test scores and thickness of the left lateral orbitofrontal area. CONCLUSION: Correlations between cortical thickness measurements by magnetic resonance imaging and cognitive performance suggest that the executive function deficit in HIV-positive patients are related to a reduction in the thickness of the frontal cortex.

The progress in the study on auditory evoked potentials / 法医学杂志

Auditory evoked potential (AEP) is the electric activities originating from auditory systems evoked by sound stimulus. AEP include cortical electric response audiometry (CERA), auditory brainstem evoked response (ABR), 40 Hz auditory event related potentials (40 Hz AERP), auditory steady-state response (ASSR), etc. For the subjects who cannot provide reliable or accurate behavioral hearing threshold, those techniques have been explored to evaluate the behavioral hearing threshold objectively. These techniques are reviewed in this article and are found that they could reflect the behavioral hearing threshold very well. CERA is difficult to operate because it is affected by the subject's wakefulness. ABR is the most widely used method currently and is not affected by the subject's consciousness, but it only reflects high frequencies. 40 Hz AERP has good sensitivity, while its results highly depend on the subject's consciousness. ASSR can be operated by using multiple frequency stimuli simultaneously to both ears and the test time is short. It is still a very difficult task to combine different techniques according to their characteristics in forensic audiology.

Cognitive control associated with irritability induction: an autobiographical recall fMRI study / Controle cognitivo associado à indução de irritabilidade: um estudo de RMf usando recordações autobiográficas

OBJECTIVE: Despite the relevance of irritability emotions to the treatment, prognosis and classification of psychiatric disorders, the neurobiological basis of this emotional state has been rarely investigated to date. We assessed the brain circuitry underlying personal script-driven irritability in healthy subjects (n = 11) using functional magnetic resonance imaging. METHOD: Blood oxygen level-dependent signal changes were recorded during auditory presentation of personal scripts of irritability in contrast to scripts of happiness or neutral emotional content. Self-rated emotional measurements and skin conductance recordings were also obtained. Images were acquired using a 1,5T magnetic resonance scanner. Brain activation maps were constructed from individual images, and between-condition differences in the mean power of experimental response were identified by using cluster-wise nonparametric tests. RESULTS: Compared to neutral scripts, increased blood oxygen level-dependent signal during irritability scripts was detected in the left subgenual anterior cingulate cortex, and in the left medial, anterolateral and posterolateral dorsal prefrontal cortex (cluster-wise p-value < 0.05). While the involvement of the subgenual cingulate and dorsal anterolateral prefrontal cortices was unique to the irritability state, increased blood oxygen level-dependent signal in dorsomedial and dorsal posterolateral prefrontal regions were also present during happiness induction. CONCLUSION: Irritability induction is associated with functional changes in a limited set of brain regions previously implicated in the mediation of emotional states. Changes in prefrontal and cingulate areas may be related to effortful cognitive control aspects that gain salience during the emergence of irritability.

OBJETIVO: Apesar da relevância de emoções de irritabilidade para o tratamento, prognóstico e classificação dos transtornos psiquiátricos, as bases neurobiológicas deste tipo de estado emocional foram raramente investigadas até hoje. Este estudo avaliou os circuitos cerebrais subjacentes à irritabilidade induzida por scripts pessoais em voluntários saudáveis (n = 11) usando ressonância magnética funcional. MÉTODO: Mudanças no sinal dependente do nível de oxigenação sanguínea (blood-oxygen level dependent signal) foram registradas durante a apresentação por via auditiva de scripts pessoais de irritabilidade em contraste com scripts de felicidade ou de conteúdo emocional neutro. Escores em escalas de autoavaliação emocional e medidas de condutância da pele também foram obtidos. A aquisição de imagens foi realizada em aparelho de ressonância magnética de 1,5 T. Os mapas de ativação cerebral foram construídos a partir das imagens individuais, e as diferenças entre as condições experimentais foram investigadas utilizando testes não-paramétricos baseados em permutações. RESULTADOS: Em comparação com scripts neutros, a apresentação de scripts de irritabilidade levou a aumentos de sinal dependente do nível de oxigenação sanguínea na porção subgenual do giro do cíngulo anterior esquerdo e nas porções medial, ântero-lateral e póstero-lateral do córtex pré-frontal dorsal (cluster-wise p-valor < 0,05). Enquanto o envolvimento do cíngulo anterior subgenual e do córtex pré-frontal dorsal antero-lateral surgiu apenas em associação com o estado de irritabilidade, aumentos do sinal dependente do nível de oxigenação sanguínea nas porções dorso-medial e dorsal póstero-lateral do córtex pré-frontal também estiveram presentes durante indução de felicidade. CONCLUSÃO: Indução de irritabilidade está associada a mudanças de atividade funcional num conjunto restrito de regiões cerebrais previamente implicadas na mediação de estados emocionais. Mudanças na atividade...

The progress in the study on slow vertex response / 法医学杂志

Slow vertex response (SVR) is one of long latency auditory evoked potentials. It is a biological and electric response originating from brain cortical neuron evoked by sound stimulus with the latency from 50 to 500 milliseconds. Of all the neuroelectric physiological audiometries, it is the earliest method applied in assessing the function of the auditory neural conduction pathway. The concept, neural generators of SVR have been introduced in this article. Influencing factors on SVR were discussed such as stimulus parameters, consciousness state, age, maturation of the subject. Applications of SVR in clinical and forensic medicine identification were also discussed.

Cortical representation of Persian word production: an fMRI study

Neural correlates of single word reading with the use of a functional MRI [fMRI] scan have been widely studied in different languages. These study patterns of cortical activation differ in different languages. In this report we used a similar technique to study cortical activation when reading single Persian words. The subjects were comprised of nine healthy right-handed bilingual individuals who performed three consecutive fMRI paradigms. Our study showed activation of the inferior frontal gyrus [IFG] when single Persian words were read. These results revealed that the pattern of brain activation during word production in Persian has a similar topography to that of English equivalents. The paradigms selectively activate word production areas and are useful in neurological assessment of the Persian population

Functional and Histologic Changes After Repeated Transcranial Direct Current Stimulation in Rat Stroke Model

Transcranial direct current stimulation (tDCS) is associated with enhancement or weakening of the NMDA receptor activity and change of the cortical blood flow. Therefore, repeated tDCS of the brain with cerebrovascular injury will induce the functional and histologic changes. Sixty-one Sprague-Dawley rats with cerebrovascular injury were used. Twenty rats died during the experimental course. The 41 rats that survived were allocated to the exercise group, the anodal stimulation group, the cathodal stimulation group, or the control group according to the initial motor function. Two-week treatment schedules started from 2 days postoperatively. Garcia, modified foot fault, and rota-rod performance scores were checked at 2, 9, and 16 days postoperatively. After the experiments, rats were sacrificed for the evaluation of histologic changes (changes of the white matter axon and infarct volume). The anodal stimulation and exercise groups showed improvement of Garcia's and modified foot fault scores at 16 days postoperatively. No significant change of the infarct volume happened after exercise and tDCS. Neuronal axons at the internal capsule of infarct hemispheres showed better preserved axons in the anodal stimulation group. From these results, repeated tDCS might have a neuroprotective effect on neuronal axons in rat stroke model.

Topographic distribution of the tibial somatosensory evoked potential using coherence

The objective of the present study was to determine the adequate cortical regions based on the signal-to-noise ratio (SNR) for somatosensory evoked potential (SEP) recording. This investigation was carried out using magnitude-squared coherence (MSC), a frequency domain objective response detection technique. Electroencephalographic signals were collected (International 10-20 System) from 38 volunteers, without history of neurological pathology, during somatosensory stimulation. Stimuli were applied to the right posterior tibial nerve at the rate of 5 Hz and intensity slightly above the motor threshold. Response detection was based on rejecting the null hypothesis of response absence (significance level α= 0.05 and M = 500 epochs). The best detection rates (maximum percentage of volunteers for whom the response was detected for the frequencies between 4.8 and 72 Hz) were obtained for the parietal and central leads mid-sagittal and ipsilateral to the stimulated leg: C4 (87 percent), P4 (82 percent), Cz (89 percent), and Pz (89 percent). The P37-N45 time-components of the SEP can also be observed in these leads. The other leads, including the central and parietal contralateral and the frontal and fronto-polar leads, presented low detection capacity. If only contralateral leads were considered, the centro-parietal region (C3 and P3) was among the best regions for response detection, presenting a correspondent well-defined N37; however, this was not observed in some volunteers. The results of the present study showed that the central and parietal regions, especially sagittal and ipsilateral to the stimuli, presented the best SNR in the gamma range. Furthermore, these findings suggest that the MSC can be a useful tool for monitoring purposes.